The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to form switching power supply controllers for use in power control systems. The previous power supply controllers generally received an input voltage and regulated and output voltage to a desired value within an acceptable range. In some cases, the power supply controllers included circuits to detect fault conditions such as the input voltage decreasing to a value that was insufficient for operating the systems receiving power from the power supply system. After detecting such a fault condition, the operation of the power supply controller was inhibited. In most embodiments, the control circuitry required to manage the power supply controller in response to the fault condition generally consumed power both during the fault condition and after the fault condition no longer existed. Additionally, the control circuitry generally required some analog elements and various digital logic elements such as gates, latches, etc. The digital and analog elements used area on the semiconductor die on which the power supply controller was produced thereby increasing the cost of the power supply controller.
Accordingly, it is desirable to have a fault control circuit of a power supply controller that reduces power dissipation both during and after a fault event occurs and that reduces the number of elements required to implement the fault control circuit.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action.